Field of the Invention
The present invention relates to a lithographic apparatus, an object positioning system, a method for positioning an object and a method for manufacturing a device.
Description of the Related Art
A lithographic apparatus is a machine that applies a desired pattern onto a substrate, usually onto a target portion of the substrate. A lithographic apparatus can be used, for example, in the manufacture of integrated circuits (ICs). In such a case, a patterning device, which is alternatively referred to as a mask or a reticle, may be used to generate a circuit pattern to be formed on an individual layer of the IC. This pattern can be transferred onto a target portion (e.g. including part of, one, or several dies) on a substrate (e.g. a silicon wafer). Transfer of the pattern is typically via imaging onto a layer of radiation-sensitive material (resist) provided on the substrate. In general, a single substrate will contain a network of adjacent target portions that are successively patterned. Conventional lithographic apparatus include so-called steppers, in which each target portion is irradiated by exposing an entire pattern onto the target portion at once, and so-called scanners, in which each target portion is irradiated by scanning the pattern through a radiation beam in a given direction (the “scanning”-direction) while synchronously scanning the substrate parallel or anti-parallel to this direction. It is also possible to transfer the pattern from the patterning device to the substrate by imprinting the pattern onto the substrate.
A lithographic apparatus usually comprises one or more objects that need to be positioned, e.g. a substrate table constructed to hold a substrate or a support constructed to support a patterning device. When an object needs to be positioned accurately, temperature control of the object and its environment may become relevant in order to minimize positioning errors caused by temperature differences. Temperature differences can occur between parts of the object and/or over time.
Temperature control may be provided in the form of a conduit being arranged on or in the object and being configured to receive a fluid within the conduit, such that the fluid can be used to transport heat from or to the object depending on the thermal condition of the object.